Circulating-tube connection



.16 192 Aug 7 J. F. ARTHUR cmcuu'rina TUBE 'conuscnon Filed Jan. 12. 1925 INVENTOR Jae 'SEHnilzur WITNESSES I v v Q ATTORNEY Patented Aug- 6, 1927.

UNITED; STATES 1,639,251 PATENT OFFKJE.

JAMES F. ARTHUR, or DIQKSON CITY, PENNSYLVANIA.

CIRGULATING-TUBE CONNECTION.

Application filed January 12, 1925. Serial No.2,083.

This invention, relates to a circulating tube, particularly designed for use 1n domestic hot water tanks. These tanks are usually cylindrical in shape, and have the 5 cold water inlet pipe and the hot water out-- let pipe connected'to the top of the tank. The inlet pipe is usually provided 'w1th an extension, herein termed a circulating tube, which extends downwardly within the tank, terminating near the bottom thereof, so that the fresh supply of cold water may pass downwardly through the hot water inthe tank, and be discharged near the bottom of the tank without interfering with or becomingmixed with thehot water in the upper part of the tank.

The common practice among plumbers has been to make the extension or circulating tube from ordinary galvanized iron pipe, but this has not proved entirely satisfactory, owing to the fact thatthe iron, even though galvanized, will become corroded through continued contact with the not water. When brass or copper pipe was 11Sed, l1OW8V8I,lt-

standard iron pipe, so that it could be cut and threaded with the standard plumbers tools, and be assembled with standard connections. This made the job quite expem sive, while the circulating pipe was much heavier than the'servi'ce required.

The object of the present invention Is. to provide a tube for the purpose stated, which is made from the usual commercial brass or co per tubing, and provided at one end with a ushing havinga standard thread, and held between a bead formed circumferentially' of the tubing and a terminal flange which is jswaged overtheend of the bushing.

the end of the tube over the end of the bush g h later is held ainst the bead a onthetube. a

' had to be of the same'size and thickness as.

Figure 5is a longitudinal section through the completed tube. I

F lgure 6 is a transverse section through a tubeof modified construction, wherein knobs are substituted for the bead.

. In carrying out the invention, I take a,

piece of light commercial brass or copper tubing 10, and place it over a revolvlng mandrel 11, having a circumferential knurled bead 12, as shown in Figure 1. Underneath the mandrel is a pivoted lever 13,

having a fork 14 in which isjournaled a roller 15, having a circumferential groove 16, adapted to mate with the knurled head 12. When the lever is actuated to press the roller 15 against the mandrel, the wall of the tubing 10 is drawn out to form'a circumferential bead 17,. as shown in Figure 2. In

this step of the process, the knurled surface of the head 12 on the mandrel engages the innerface of the tube, and causes the latter 7 to revolve with the mandrel, so that a uniform bead 17 is formed inthe tube.

A brass bushing 18 is now placed over the end of the beaded tube, as shown in Figure 3, with its polygonal head 19 abutting against the head 17. This bushing is formed with standard threads 20, and its inner end is reamcdout to form an internal outwardly inclined shoulder, as shown at 21,

before being placed on the tubing. The bead 17 is formed at the proper distance from the through and slightly beyond the shoulder 21 of the bushing.

The tubelO with the bushing thereon isnow placed in a vise 22, in front of a spinning tool 23, which is secured in a spinning arbor 2 t,slidably mounted in a bronze bearing 25. The spinning tool 23 is formed with a beveled shoulder 26, which is adapted to engage the end of the tubing 10 and swage .end of the tubing, so that the latter'projects' it over the shoulder 21 of the bushing, forming a flange 27, as shown in Figure 5. During this step in the process, the bead 17 forms an abutment against which the bush-j ing is held until the swaging operation is completed, and the bushing becomes, in efi'ect an integral part .of the tube.

Since the motion of the bead 17 ismerely that of an abutment, its particular shape is not important. In Figure 6, I have shown a modi thetube 10, is formed with a lurality of outwardly pressed knobs 29, which, for the cation in which a tube 28 similar. to

purposes of the present invention, are the equivalent of the bead 17. These knobs may be made by the use of a press with a male and female die. Instead of the abutments 17 or 29, abutments of solder could be used in their place.

It will be noted that the internal diameter of the bushing is substantially the same as the external diameter of the body of the thin-walled tube, so that there is no lessening of diameter of the tube and consequent constriction of flow.

It will be understood, of course, that the usual commercial'brass or copper tubing is so light and thin that it is impossible to thread it without cutting through the wall, or so weakening it that it can not be used. The present invention provides a practical method for reinforcing the end of such a tube, and providing it with standard threads, so that it may be used for the purpose stated without any needless expense, and for all practical purposes it will be just as durable, or even more durable than brass or'coppcr pipe having the same size and thickness as a standard iron pipe.

While I have described the invention specifically with reference to its use in connection with the installation of hot Water tanke it will be obvious that the invention is capable of other uses, and that other modifications may be made therein without departing materially from the essential features of the invention. It is, therefore, my intention to include all such uses and modifications within the scope of what is claimed. Where an absolutely water or air tight joint is desired, the bushing may be soldered, brazed, or welded to the tube.

What is claimed is:

1. A circulating tube for hot water boilers comprising in combination a thin walled tube of uniform wall thickness throughout,

provided with an outwardly extending.

shoulder portion forming an abutment, and a bushing of heavier metal positioned on one end of the tube, said abutment being spaced in from the end of the tube a distance equal to the length of the bushing, the end of the.

tube being expanded outwardly into engagement with the bushing, the abutment being positioned just beyond the inner end of the bushing and bearing against the extreme inner end of the bushing for holding the bushing in place on the tube, the bushing being exteriorly threaded and provided exteriorly with a portion to which a wrench may be applied, the threaded portion and the wrench receiving portion being located between the expanded end of the tube and the abutment.

2. A circulating tube for hot water boilers comprising in combination a thin walled tube of uniform wall thickness throughout, provided with an outwardly extending shoulder portion forming an abutment, and a bushing of heayier metal positioned on one endof the tube, said abutment being spaced in from the end of the tube a distance equal to the length of the bushing, the outer end of the bushing being provided with an annular, outwardly inclined shoulder, the end of the tube being expanded outwardly into engagen'ient withsaid annular shoulder, the abutment being positioned just beyond the inner end of the bushing for holding the bushing in place on the tube, the bushing being exteriorly threaded and provided exteriorly with a portion to which a Wrench may be applied, the threaded portion and the wrench receiving portion being located between the expanded end of the tube and the abutment.

In testimony that I claim the foregoing as my own, I have hereto affixed my signature.

JAMES F. ARTHUR. 

